Square D LJA36400CU31X - 400 A, 3-Pole Plug-In Circuit Breaker | AmpState

Meet reliable protection for demanding power distribution: the Square D LJA36400CU31X, a 400A, 3-pole plug-in molded case circuit breaker built to safeguard panelboards and loadcenters from overcurrent and short circuits. Designed for fast, confident protection, this unit is ready to endure the rigors of commercial, light industrial, and residential applications alike.

Key reasons to choose the LJA36400CU31X:

• Fast plug-in connection enables quick installation and hassle-free replacement, reducing downtime during upgrades or service calls.
• Thermal-magnetic trip unit delivers stable, repeatable protection by responding to both overloads and short circuits with precise, predictable trip behavior.
• Three-pole, 400A design supports three-phase systems and high-current distribution, making it ideal for demanding panels and load centers.
• OEM-compatible mounting engineered to pair with matching Square D panelboards and loadcenters for a seamless fit and coordinated protection schemes.
• Versatile application suited for residential, commercial, and light industrial electrical protection needs, providing dependable branch-circuit safety across environments.

What problems does it solve? When you need robust protection without complicating installation, this plug-in MCCB offers a clean, secure fit that stays put in vibration-prone environments. If you’re upgrading an existing panel or expanding a new installation, the LJA36400CU31X provides reliable, code-flexible overcurrent and short-circuit protection that you can count on during daily operation and fault events.

Use cases at a glance

• Upgrading commercial panelboards where three-phase distribution and high-current protection are required
• Installing or expanding panelboards and loadcenters with a single, rugged plug-in breaker
• Replacing aging protection devices to restore dependable circuit protection quickly

Technical snapshot

• Type: Thermal-magnetic molded case circuit breaker
• Amperage rating: 400A
• Poles: 3
• Mounting style: Plug-in
• Part number: LJA36400CU31X

For installers and facility managers seeking a proven, plug-in solution that keeps three-phase systems protected with precision, the Square D LJA36400CU31X stands out by blending quick installation, reliable trip performance, and OEM-aligned compatibility in a single, dependable package.